Certain engines, such as those found in the Chevrolet Cruz and Buick encore, have a check valve in the intake manifold. These engines have a high failure rate associated with the check valve being dislodged from its intended position.
The intake manifold basically has two chambers. The intake chamber and the PCV chamber with the check valve, which is an umbrella or mushroom like diaphragm that is retained in position by a nipple that is held with a press fit. The check valve allows positive crankcase ventilation (PVC) of combustion gases that by pass the piston rings into the crankcase. When the check valve is open, the PCV recycles the air into the intake chamber. When there is a load that creates a pressure boost, the check valve closes and prevents the flow of air into the crankcase. When the check valve is dislodged and fails to function properly, there is a back flow into the crankcase.
In other words, proper engine operation, the check valve allows gas to freely flow into the intake chamber when the engine is under vacuum, but block that gas flow under boost conditions. While the original equipment manufacturer (OEM) intake manifold check valve initially works well, it fails prematurely and can disappear altogether when it is dislodged.
Some prior attempts are correcting the problem have suggested method of modifying the manifold and there are kits available for that purpose. However, such modification may have unintended consequences if not performed by a skilled mechanic or may void some aspects of the manufacturer's warranty.
Accordingly there is a need for better securing the check valve in its proper operating position.